Could hybrid ecosystems save native forests in Hawaii?

The lowland wet forests of Hawaiʻi are in serious trouble. Human activity over the centuries has nearly decimated these unique ecosystems.

“They are pretty much doomed,” said Rebecca Ostertag, a biology professor at the University of Hawaiʻi. “There is so little of them left and what is left is highly, highly invaded by very invasive plant species. The whole system could disappear.”

The situation is so critical that even with constant weeding, many scientists and resource managers believe it is not economically or practically possible for these forests to return to an all-native ecosystem.

“Unless we do some kind of management and restoration, we are not going to have native species in low elevation forests,” said Ostertag.

A research team led by UH Hilo is testing a new strategy at the Keaukaha Military Reservation in Hilo in hopes of saving some of Hawaiʻi’s low elevation forests. The team is creating “hybrid ecosystems” where invasive species are cleared out and replaced with a combination of native and non-native plants. The selected non-native plants are not invasive and have traits that compliment the native plants.

“Our idea is that we will create better functioning forest that will be better at keeping out invasive species,” said Ostertag.

The goal is a self-sustaining forest where native species can once again regenerate and thrive, without much work after the initial investment.

Reforestation work in Hilo’s low elevation forests uses a hybrid ecosystem strategy that involves planting both native and non-native plants.

“Our hybrid concept is something that is unique and pretty controversial out there, but we are hoping that it will have relevance beyond Hawaiʻi,” said Ostertag. “Not only are we just asking some management questions, we are asking questions, about fundamentally, how different plant communities assemble.”

The project also offers a tremendous opportunity to UH Hilo undergraduate and graduate students, interns from other universities and local high school and middle school students to be a part of an ongoing scientific experiment.

“I learned how to take down really big trees for one,” said Taite Winthers-Barcelona, a UH Hilo student and intern for the U.S. Forest Service. “I also learned how to collect data on tree heights.”

“I feel like you are a lot more attached to your work, you are a lot more passionate about it if you’re out there doing the work hands on rather than being stuck in a dorm room reading about it,” said Stephen McAuliffe, a Humboldt State University student who worked on the project during his summer break.

“It is a great experience for them to see what it is like and to understand also what science is involved and what scientists do,” said Ostertag.

In this case, UH Hilo scientists and students are thinking outside of traditional approaches in forest management to save an important part of Hawaiʻi’s heritage.

“If we let these types of forests go, than we are really losing a piece of HawaiʻI,” said Ostertag. “We are letting extinction happen.”

I read your article on how can we save the ecosystems in Hawaii. I’ve always been interested in the native plants but never had the opportunity to learn. Most of my grandparents passed on when I was at a young age. They were the ones that had the knowledge about the native plants and the purposes of the medicinal aspects of them. Do you think that I would be able to help with your folks research providing it is at an available time that I will be able to attend. I’m an undergraduate Uhh student and maybe graduating soon. An interested student.

Thanks for your interest. You can contact the Rebecca Ostertag, a biology professor at the University of Hawaiʻi at Hilo, for more information on this project. If you click on her name in the story above you’ll get her UH Hilo website with her contact information.

I like your idea and think that many of the Islands could use your concept. In some areas where lack of water is a problem you might think about using treated wastewater from the treatment plants. The Wastwater plants would not have to put the R1 water down injection wells that can enter the ocean. The second benifit would be that the trees could use the nutrients from the water and filter them out before they would enter the ground water. There would have selective sites near the treatment plants so that the cost would not be so expensive and Maui might be a good place to start.